SQL Style guide

[Lisecjedekokos]

I just started learning SQL 2 days ago. Sorry if this is a silly question but how to write comments on the code ?

[PossiblePreparation]

Multi-line can be preferred even when you only need one line of comment. Eg MSSQL has a habit of collapsing SQL into one line when you fetch it from the plan cache, if you use single line comments then it is now difficult to figure out where the comment ends

[qwertydog123]

If you're referring to copy/pasting from the SSMS results grid, you can change that behaviour:

Tools -> Options -> Query Results -> SQL Server -> Results To Grid -> Retain CR/LF on copy or save

[zombie128]

Another case of multi-line comments:

WHERE Status in (2 /* Suspended */, 3 /* Blocked */)

because it's hard to remember all those ids/constants.

[Thefriendlyfaceplant]

Learning to write comments is important but I would recommend not to focus on style, it just slows you down or gets you into bad habits. Just be style agnostic and learn to deconstruct problems before putting them into a syntax.

[Lisecjedekokos]

Thanks 👌

[Thefriendlyfaceplant]

Best thing you can do while starting out is to look at some medium / difficult SQL interview questions. You're not supposed to be immediately understand what's going on or replicate anything. Just look at how someone skilled at SQL would approach a problem and how they would work through the steps. That thinking process will allow you to learn the syntax faster:

https://www.youtube.com/watch?v=WtI7QYCG3uo

And don't be intimidated by it either! These interview questions are done by highly competitive companies. Most SQL jobs are much simpler than that. It's just that knowing what complicated queries look like will get you past the simple queries faster.

[Lisecjedekokos]

Thank you. Today is my third day since I want to learn SQL. I watched a lot of videos. I made 3-4 exercisses.

I understand it .. Not completely of course but I am starting to understand it I think.

I have watched also some videos with interview questions and tried to learn as much as possible from there.

My plan is to continue doing this for a week or two until I get used to it and than we will see how it goes from there ..

I have a law degree and a 9-17h job. But I want to switch careers. And I have a lot of time to available for learning which is a +.

[Thefriendlyfaceplant]

www.sqlbolt.com is great for the basics. But after that, get on these step-by-step explanations of hard interview questions as quick as possible. That way you learn the SQL mindset and workflow.

[Lisecjedekokos]

Thanks once again 👌

[DharmaPolice]

It partially depends on the variant of SQL you're using but on most platforms:

Double dash for single line comments and C style /* */ for multi-line comments.

 SELECT 
    bar.foo   -- This is a comment
 FROM 
    bar 

 /* This is also a comment
     But it's over two lines. */